Apparatus for receiving and determining the authenticity of papers such as securities, stocks, bonds, notes, and the like have been known for many years. Typically, such security validators have been of either the tray acceptor type, in which the security is deposited in a tray for transport to a testing station, or the slot acceptor type, in which the paper is inserted into a slot and transported by rollers to the testing station. A universal slot acceptor is taught in the aforementioned U.S. patent application Ser. No. 085,394, for "SECURITY VALIDATOR." Such a device is considered universal in that it utilizes a programmable microprocessor to allow the security validator to be adapted for use in determining the authenticity of a large variety of documents. For example, the microprocessor may be programmed to conduct tests on various denominations of United States currency, while it may be similarly programmed for receiving and testing the authenticity of currencies of various foreign countries. The microprocessor allows the hardware of the security validator to remain substantially fixed, irrespective of the particular currency to be validated. In principle, changes need only be made to the software of the system, defining the tests peculiar to a particular denomination of the currency of the particular country in which the validator is to be used. Accordingly, a single structure has been developed for worldwide use, with software changes being made as a function of the country in which each specific apparatus is to be placed.
Applicants have found that, throughout the world, while currencies are of somewhat standard sizes, currency width does vary from country to country, and from denomination to denomination within a given country. Utilizing a slot of fixed width to receive the note requires that the slot be of sufficient width to accommodate the widest note which might possibly be introduced to the validator. In such case, the slot must be of sufficient width that when narrower pieces of currency are introduced, there is a significant likelihood that the note will be received at the test station out of registry, or misaligned, with the testing circuitry, lamps, reticles, sensors, and the like. The result is erroneous rejections of valid currency. The validator then gives the appearance of being inaccurate and unreliable when, in fact, the problem is merely the result of misalignment of the offered paper with the test apparatus.
To overcome the problem of misregistration, the validator of the aforementioned copending patent application might be provided with slots of widths determined by the widths of the various currency to be introduced to the particular apparatus. However, such provision defeats the concept of a universal slot acceptor and validator, since substantial hardware changes would be required as a function of system application. As a result, the benefits sought to be obtained by a universal validator, would be defeated.